private IEnumerator <Nalu> GetAllNalus(Stream fs)
{
fs.Seek(0, SeekOrigin.Begin);
uint offset = 0;
ReadHeader(fs, ref offset);
for (; ;)
{
long fsPos = fs.Position;
FLVTag tag = ReadTag(fs, ref offset);
if (tag != null)
{
var x = GetNalus(tag, fsPos);
while (x.MoveNext())
{
yield return(x.Current);
}
}
else
{
break;
}
}
yield break;
}
//tag type, tag size, tag data
private FLVTag ReadTag(Stream fs, ref uint offset)
{
try
{
FLVTag result = new FLVTag();
//prev tag size
if (fs.ReadBlock(4) == null)
{
return(null);
}
offset += 4;
result.tagType = fs.ReadU8();
offset += 1;
result.tagSize = fs.ReadU24BE();
offset += 3;
//timestamp
fs.ReadU24BE();
offset += 3;
//timestamp ext
fs.ReadU8();
offset += 1;
//stream id
fs.ReadU24BE();
offset += 3;
result.tagDataOffset = offset;
// tag > 10M, maybe parse in wrong position
if (result.tagSize > 10485760)
{
throw new FLVToolException(fs.Position, "Tag data > 10M, maybe an error.");
}
result.tagData = fs.ReadBlock(result.tagSize);
offset += result.tagSize;
return(result);
}
catch (EndOfStreamException)
{
return(null);
}
}
private IEnumerator <Nalu> GetNalus(FLVTag tag, long fsPos)
{
if (tag.tagType == 9)
{
MemoryStream ms = new MemoryStream(tag.tagData);
uint offset = tag.tagDataOffset;
//frame type and codec id
uint tmp = ms.ReadU8();
offset += 1;
if ((tmp & 0xf) == 7)
{
uint avcpkttype = ms.ReadU8();
offset += 1;
if (avcpkttype == 1) //nalu
{
//composition time
ms.ReadU24BE();
offset += 3;
//avcc to annex-b
while (ms.Position < ms.Length)
{
Nalu nalu = new Nalu();
nalu.type = Nalu.NaluType.OTHER;
nalu.offset = offset;
uint len = ms.ReadU32BE();
offset += 4;
nalu.len = len;
nalu.data = startcode.Append(ms.ReadBlock(len));
offset += len;
yield return(nalu);
}
}
else if (avcpkttype == 0) //sps pps
{
//???
ms.ReadU24BE();
offset += 3;
//conf ver
ms.ReadU8();
offset += 1;
//avc profile
ms.ReadU8();
offset += 1;
//profile compatibility
ms.ReadU8();
offset += 1;
//avc level
ms.ReadU8();
offset += 1;
//length size - 1
uint len_minus_one = ms.ReadU8();
if (len_minus_one != 0xff)
{
throw new FLVToolException(fsPos + ms.Position - 1, "lengthSizeMinusOne != 3 in SPS, not supported");
}
offset += 1;
//sps count | 11100000
uint spsCntRaw = ms.ReadU8();
int spscount = (int)(spsCntRaw) & 0x1f;
offset += 1;
//sps
for (int i = 0; i < spscount; ++i)
{
Nalu nalu = new Nalu();
nalu.type = Nalu.NaluType.SPS;
nalu.offset = offset;
uint spslen = ms.ReadU16BE();
offset += 2;
nalu.len = spslen + 2;
nalu.data = startcode.Append(ms.ReadBlock(spslen));
offset += spslen;
yield return(nalu);
}
//pps count
int ppscount = (int)(ms.ReadU8());
offset += 1;
//pps
for (int i = 0; i < ppscount; ++i)
{
Nalu nalu = new Nalu();
nalu.type = Nalu.NaluType.PPS;
nalu.offset = offset;
uint ppslen = ms.ReadU16BE();
offset += 2;
nalu.len = ppslen + 2;
nalu.data = startcode.Append(ms.ReadBlock(ppslen));
offset += ppslen;
yield return(nalu);
}
}
}
}
}
